This invention relates to a digital filter for picture data and a digital filter system.
In a digital signal processing system for picture processing, processing by a filter, in particular a low-pass filter, is executed frequently.
In sampling rate conversion, for example, input picture data is upsampled to a sampling frequency equal to a least common multiple between an input rate and an output rate and downsampled after bandwidth limitation by a low-pass filter for generating output data having a desired sampling frequency.
With a conventional digital filter adapted for processing picture data signals by a low-pass filter, ringing (overshoot) is increased if a flat band is to be increased in width, while the bandwidth is decreased if the ringing is to be reduced.